equations

Bedside schwartz?

.413 x height in cm / Serum creatnine

Hyperbolic Emax model?

Effect= Emax * serum conc. /(EC50 + serum conc)

Volume distribution?

Vd= #of drug given/ serum conc.

Clearance?

Rate of elim./serum conc.
OR Vd * Ke
(ke is elimination constant)

Half life equations?

.693/ke
or (.693 * vd)/CL

Bioavailability?

AUC Oral
Dose IV/ (AUC IV
Dose oral)
AUC is area under the curve

Hepatic clearance (low extraction ratio)?

H = Fraction of drug unbound * intrinsic clearance

Hepatic clearance (high extraction ratio)?

Equal to blood flow through liver

Renal clearance?

(24hour urine volume * conc. of drug in urine)/ Conc. in serum

Cockroft Gault kidney clearance?

(140-age )
(wt in kg)/ (72
serum creatnine)
-For women * answer by .85

Loading dose?

LD = Vd* steady state conc.

Maintenance dose?

(Clearance * C steady state)/bioavailibility

Physiologic Dead space

VT X (PaCo2 - PECo2)/ Paco2
PECO2 = Partial pressure of expired CO2

Minute ventilation?

VE=VT x RR

Alveolar ventilation?

VA=(VT-VD ) X RR

Pulmonary Vascular resistance?

PVR=( P pulm artery- P left atrium)/CO

Resistance to blood flow?

8nl/piR^4
n is viscosity
l is length
R is radius

Alveolar gas equation?

PAO2=PIO2-PaCO2/R
R is usually .8
PIO2 is usually 150 mmHg